Apparatus for the continuous manufacture of thermoplastic resinous containers

ABSTRACT

Apparatus for the continuous manufacture of containers from a thermoplastic resin, comprising three rotaries; a parisontransferring rotary, a blow-molding rotary and a rotary for removal of the product and for pinhole test. The first rotary is arranged as a rotary-type transferring device between the molding machine and the extruder, in which the continuously extruded tubular parison is continuously stretched and cut to a desired length, and this cut parison, after rotation thereof by 90*, is inserted into one of the metal molds in the point of contact with the second rotary being a blow molding rotary, whereby the waste of material as in the conventional rotary blow molding machines can be eliminated. The second rotary is equipped with several or dozens of sets of metal molds and their tightening means. These metal molds are synthetic resin blow-molding ones in which sealing of the product and utilization of the material can be performed efficiently. In this case, two sets of split molds are combined with their container bottom-forming portions opposed to each other and a blow pin is arranged between said bottom forming portions so as to form two containers at a time, and a pressing mechanism for closing the top of the container and adapted to be movable at right-angles to the split face of the mold is provided, thus improving the operational efficiency and reducing remarkably scraps in the ranges of the top and bottom of the container. Normally, in the case of resins from which narrownecked containers cannot be made by blow molding and biting off as in the case with vinylidene chloride, only large necks than the diameter of the parison can be formed. Of course, it is possible to make the diameter of the neck substantially equal to or smaller than that of the parison by arranging any guide at the position of the neck, but this leads to reduction of the yield by an amount corresponding to the width of the guide. According to the present invention, the parison is pressed in a direction perpendicular to the split mold, thereby to realize the same effect as that of the guide and moreover to enable the container to be sealed tight enough to prevent penetration of bacteria. In order to facilitate sealing of the container at the bottom immediately after blow molding, high frequency electrodes may be provided at the bottom-forming portion of the metal mold. The so produced container is taken out from the mold by grasping it at the portion grasped for transfer from the first to the second rotary, as soon as the mold is opened at the point of contact with the third rotary. Then, the unnecessary portion between the bottoms of two containers is removed by a bottom cutter while air-cooling them and at the same time the body of the sealed container is compressed with a certain pressure to check it for freedom from pinholes. Finally, the finished containers are sorted as acceptable or not an are made to fall down.

United States Patent 7 2] lnve ntors Shinsuke Yoshiltawa;

Yuji Sawa, both of Fukushima-Ken, Japan [21] Appl. No. 851,289

[22 Filed Aug. 19, 1969 [45} Patented Aug. 3,1971

[73] Assignee Kureha Kagaku Kogyo Kabushiki Kaisha Tokyo-to, Japan [32]Priority Aug. 21, 1968, Aug. 22, 1968, Aug. 22,

[3 3 Japan [3 l 43159193, 43159516 and 43/59515 [54] APPARATUS FOR THECONTINUOUS MANUFACTURE OF THERMOPLASTIC RESINOUS Primary Examiner-.1.Spencer Overholser Assistant Examiner-Michael 0. SuttonAttorney-Wenderoth, Lind & Ponack ABSTRACT: Apparatus for the continuousmanufacture of containers from a thermoplastic resin, comprising threerotaries; a parison-transferring rotary, a blow-molding rotary and arotary for removal of the product and for pinhole test. The

first rotary is arranged as a rotary-type transferring device betweenthe molding machine and the extruder, in which the continuously extrudedtubular parison is continuously stretched and cut to a desired length,and this cut parison, after rotation thereof by 90, is inserted into oneof the metal molds in the point of contact with the second rotary beinga blow molding rotary, whereby the waste of material as in theconventional rotary blow molding machines can be eliminated. The secondrotary is equipped with several or dozens of sets of metal molds andtheir tightening means. These metal molds are synthetic resinblow-molding ones in which sealing of the product and utilization of thematerial can be performed efficiently. in this case, two sets of splitmolds are combined with their container bottom-forming portions opposedto each other and a blow pin is arranged between said bottom formingportions so as to form two containers at a time, and a pressingmechanism for closing the top of the container and adapted to be movableat right-angles to the split face of the mold is provided, thusimproving the operational efficiency and reducing remarkably scraps inthe ranges of the top and bottom of the container. Normally, in the caseof resins from which narrow-necked containers cannot be made by blowmoldingand biting off as in the case with vinylidene chloride, onlylarge necks than the diameter of the parison can be formed. Of course,it is possible to make the diameter of the neck substantially equal toor smaller than that of the parison by arranging any guide at theposition of the neck, but this leads to reduction of the yield by anamount corresponding to the width of the guide. According to the presentinvention, the parison is pressed in a direction perpendicular to thesplit mold, thereby to realize the same effect as that of the guide andmoreover to enable the container to be sealed tight enough to preventpenetration of bacteria. In order to facilitate sealing of the containerat the bottom immediately after blow molding, high frequency electrodesmay be provided at the bottom-forming portion of the metal mold. The soproduced container is taken out from the mold by grasping it at theportion grasped for transfer from the first to the second rotary, assoon as the mold is opened at the point of contact with the thirdrotary. Then, the unnecessary portion between the bottoms of twocontainers is removed by a bottom cutter while air-cooling them and atthe same time the body of the sealed container is compressed with acertain pressure to check it for freedom from pinholes. Finally, thefinished containers are sorted as acceptable or not an are made to falldown.

PATENTEU ms 3 Ian 3, 59B, 3 1 5 sum 1 0F 7 k 23 1 FIG.|

SHINSUKE YOSIIIKAWA and YUJI SAWA,

I N VEN TORS Attorneys PATENTEU AUG 3 l97| SHEET 2 0F 7 SI IINSUKEYOSHIKAWA and YUJI SAWA,

I NVENTORS wmmmam Attorneys PATENTEU AUG 319?! SHEU 3 0F 7 FIG. 6

PRIOR ART 5 FIG. 7

SI'IINSUKE YOSHIKAWA and YUJI SAWA,

INVENTOR. 5

Attorneys PATENTEU Aus 31971 3,596,315

sum u 0F 7 SHINSUKE YOSHIVAWA and YUJI SAWA,

INVENTOR. S

BY MM, $11M Attorneys PATENTEDAUG 3l97l 3,596,315

SHEEI S [If 7 SHINSUK'E YOSHIKAWA and YUJI SAWA,

INVENTOR S BYMMJZ mid/.1 M

Attorneys PATENTEDMI'G am: 3596315 SHEET 7 OF 7 FIG. l5

SHINSUKE 'JOSHIKAWA and YUJI SAWA, INVENTOR.

Max-l1 M Attorney:;

APPARATUS FOR THE CONTINUOUS MANUFACTURE OF THERMOPLASTIC RESINOUSCONTAINERS BACKGROUND OF THE INVENTION In the conventional art offorming containers of thermoplastic resin in a high efficient manner,the material is extruded by an extruder into a continuous pipe(hereinafter referred to as parison"), the thus formed parison istransported into a blow-molding machine, where it is formed into desiredforms in a metal mold, and then the formed product is removed from themetal mold, with for instance, knockout pins to fall down.

When vinylidene chloride resin is to be formed in such a blow-moldingmachine,.the parison must be stretched longitudinally prior to blowmolding, thereby to improve the material strength of the product. In arotary blow-molding machine used hitherto for accomplishing thispurpose, several sets of blow-molding split molds are arranged at equalintervals around a rotary base adapted to rotate about a vertical orhorizontal axis, wherein the parison extruded in the circumferentialdirection of said base is pinched at one end thereof by a pair ofnippers associated with said metal mold to be stretched by rotation ofsaid base, and then it is sealed in the metal mold by closing this moldand blown and formed by blowing a fluid into the parison. Thisblow-molding machine is simple in its construction and operatedincooperation with an extruder, thus permitting the extruded parison tobe immediately stretched and blow molded in succession, but it has thefollowing disadvantages:

I. Since the blow-molding metal molds arranged around the base must bespaced from one another from constructive point of view, the section ofparison between two adjacent molds is of no use, whereby the rate ofmaterial utilization is decreased. Especially, in the case of vinylidenechloride, it is difficult to reuse the scrapped material, thus leadingto an economical disadvantage;

2. When a rotary molding machine is to be used for manufacture ofbottles or the like different sizes by exchanging the metal molds, thewaste of material is increased with smaller metal molds;

3. It is difficult to automatize the process of separating the moldedproduct from the metal mold and the trimming process of cleanly removingthe portion of parison pinched by the closed mold. In the case ofpolyethylene, the molded products can be taken out as a chainlike trainand then trimmed. Such a method cannot be, however, applied forvinylidene chloride, for the containers made thereof will be subject todeformation.

4. When bottles or other containers are manufactured from thermoplasticsynthetic resins, particularly from highly flexible ones such aspolyethylene and vinylidene chloride, it is necessary to seal them forthe purpose of preventing deformation thereof during transportation andpenetration of bacteria and foreign matters thereinto. That is, it isusual that the containers are transported in the sealed condition andcleanly cut at the port just before it is filled with contents. Hence,for the manufacture of such sealed containers as described above themolded product must be welded at the bottom thereof by high frequencyheating or sealed at the blow pinhole by heating or high frequencywelding while being in the metal mold or after separated therefrom.

SUMMARY OF THE INVENTION A principal object of the present invention isto solve the above-mentioned problems and to provide an improvedapparatus capable of performing successively longitudinal stretching ofthe parison blow-molding, sealing of the molded product, separation ofthe product from the metal mold, and pinhole testing ofthe product.

The above object and other objects of the invention have been attainedby'the apparatus comprising a parison transferring rotary adapted totake the parison continuously from an extruder, said rotary comprising abase rotating around its center axis, several support rods projectedlaterally from said base and arranged at equal intervals around saidbase, a tube fitted loosely on each of said support rods and controlledfor movement along said support rod and for rotation by with respect torotation of said base, connecting pieces fixed to the outer end of saidtube so as to form a T-shaped, holding means comprising two pairs ofnippers secured to both ends of said connecting pieces and adapted to beopened and closed in relation to the rotation of said base, and cuttingblades provided on one of said pairs of the nippers located forward withrespect to the direction of rotation of said base, whereby said forwardpair of the nippers are made to grasp the parison to stretch it with therotation of said base for moving said nippers at a linear velocityhigher than that at which the parison is extruded from said extruder andthen the backward pair of nippers nips the parison and at the same timeas this nipping the forward pair of nippers of the succeedingparisonholding means grasps the parison,'said cutting blades beingarranged so that the parison is cut off at a position between said bothpairs of nippers, and said parison holding means being constructed andarranged in such a manner that said holding means rotates by 90 aftersaid cutting of the parison thereby to bring the cut and stretchedparison as held as above into parallel to the rotating axis of said baseand to insert it into one of two-piece split metal molds of thefollowing blow-molding rotary, said molds being mounted in parallel tosaid rotating axis; and a blow molding rotary comprising a rotatingdisc, several tightening devices arranged at equal intervals around saiddisc, said tightening device including said split mold constructed tohave a form obtained by joining bottom portions of two containers, ablow pin adapted to be inserted between the bottoms of two containers tobe formed, and nippers mounted on both ends of one split of said splitmold in the direction at right angle with the split surface of the mold,said nippers being adapted to open when the mold is opened and closewhen the mold is closed thereby to compress the parts of the parisonprojecting from the ends of the mold; and means adapted to rotatesynchronously and continuously said two rotaries.

The above objects and characteristic feature and function of theinvention will be clearly understood by the following description inconjunction with the accompanying drawings, in which the same orequivalent numbers are designated by the same reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I. is a plan view of the wholeparts of an apparatus ac cording to the present invention;

FIG. 2 is a front elevational view of the apparatus of FIG. 1; FIG. 3 isa view ofa parison holder of the apparatus of FIG.

FIG. 4 is a side elevational view of the parison holder of FIG. 3, saidholder being in a state turned by 90;

FIG. 5 is a view seen from the right of FIG. 3;

FIG. 6 is a sectional view showing molding state of the neck ofa bottlebeing molded by a conventional method;

FIG. 7 is a sectional view similar to FIG. 6 in the case of the presentinvention;

FIG. 8 is a vertical sectional view taken along the line VIII-VIII inFIG. 9, ofthe metal mold according to the present invention;

FIG. 9 is a side elevational view of the metal mold viewed from theright of FIG. 8;

FIG. 10 is a side elevational view of the opened metal mold;

FIG. 11 is a side elevational view of the mold-tightening devicewhich-encloses mold therein;

FIG. 12 is a plan view ofthe device of FIG. 11;

FIG. 13(a) and (b) are, respectively, a plan view of the bottom cutteropened and a plan view of that closed;

FIG. I4 is a sectional view taken along the line XIV-XIV of FIG. 13;

FIG. 15.is a schematic view of a sealed container while beingcompressed; and

FIG. 16 is a schematic view of the pressing mechanism to be used in theinvention.

DETAILED DESCRIPTION OF THE INVENTION The present invention will bedescribed hereinbelow in con- I necting piece 30, which carries on bothends two pairs of nippers 31 and 31a. The parison is held or released bythe nippers in such a nianner that movable jaws 39, 390 are pressedagainst or separated from the fixed ones 40, 40a by means of piston rods33, 33a operated by air cylinders 32, 32a. Cutting blades 41 and 42 areprovided on the jaws 39 and 40 located forward in the direction ofrotation of the base 27, so that the parison is cut off at the same timewhen .the jaws 39 and 40 nip it 'therebetween. Formed in the tube 29 isa cam slot 34, into which a pivot 35 fixed to the support rod 28 isengaged. A lever 36 pivoted to the base 27 at a pivotal shaft 37 isengaged at its one end in an annular groove 24 formed in the tube 29 andat its other end in a fixed guide groove 38, This first rotary iselectrically energized through a slip ring and a brush 6 and controlledthrough limit switches and magnetic valves which are not shown.Compressed air is supplied through a rotary joint 15. I

The parison 26 continuously extruded from the extruded E t is conveyedin a direction tangential to the circle of rotation of the holder 4rotating together with the base 27, as shown by the arrow of FIG. 1, andthe base isrotated in such a way that the linear velocity of the holder4 exceeds the velocity of extrusion of the parison. Now, the firstrotary I operates as follows:

l. The parison 26 is cut off at its forward end when it is nipped bytheforward pair of nippers 310 (left in FIG. 5). In this state, the nippers31 are not yet at work.

2. The parison is stretched with rotation of the base 27, because thelinear velocity of the nippers 31 is higher than that at which thematerial is supplied, and the holder 4 reaches the position a of FIG. 1.

3. Then, the backward pair of the nippers 31 are closed thereby to holdthe parison stretched between the nippers 31 and 31a.

4. As soon as the backward pair of the nippers 31 of the holder 4 in theposition a are closed, the forward pair of the nippers 31a of the holderin the adjacent position h are closed thereby to cut off the parisonbetween said nippers of said both holders and the holder 4 in theposition It moves to the position 11, thereby to stretch the parison asexplained before. As the base 27 rotates, these operations are repeatedin the individual holders one after another.

5. While the holder 4 carrying the stretched parison is moving from c tod, the lever 36 moves from the position of FIG. 3 to that of FIG. 4under the action of the guide groove 38, thereby to extrude the tube 29along the support rod 28, whereby the tube 29 is turned by 180 in thedirection of arrow in FIG. 5 owing to engagement of the cam slot 34 withthe pivot 35, thus bringing the holder 4 to its longitudinal position'asshown in FIG. 4.

6. When the longitudinally positioned holder 4 reaches the position 2,it encounters one of eight sets of tightening devices 9 arranged aroundthe second rotary 2 which has rotated synchronously in the direction ofarrow thereof, where the parison is inserted into the opened metal mold43. Upon insertion of the parison into the metal mold 43, this metalmold is closed, thereby to pinch the stretched parison therein.Subsequently, the nippers of the holder 4 are opened to release theparison and then transfered toward the position f.

7. The holder 4 which has released the parison therefrom turmagain byduring its transference from the position 3 to h', in the oppositedirection through the mechanism comprising the guide groove 38, lever36, cam slot 34 and pivot 35. Thus, it gets ready to hold the nextparison.

In this way, the extruded tubular parison is successively stretched,held and transfered to the second rotary by means of the eight sets ofparison holders one after another.

The tightening device 9 of the second rotary is so constructed as shownin FIGS. 11 and I2. Secured to this device is a two-piece split mold 43in a vertical plane, said mold being adapted to open or close about afulcrum 71. A pneumatically operatable air cylinder 67 is secured to aframe 66. When the cylinder 67 receives a signal in a predeterminedposition, a fork 69 is pushed by a piston rod 68, thereby to press themold parts 48 and 49 through connecting plate 70 and 70a, thus closingthe mold into the positions 48b and 49b. At this state,

' the connecting plates 70 and 7011 take the positions 70hand are fixedthere by toggling action. After these operations, the cylinder 67 isactuated in the opposite direction by a compressed air caused by anothersignal, thereby 'to return the piston rod 68 and fork 69, thus openingthe metal mold 48, 49.

The inner construction of the metal mold, which forms an important partofthe present invention, will be now explained. In FIGS. 6 to 10,numerals 48, 49 and 48a, 49a designate respectively two sets of metalmolds adaptedto form a bottle. They are mounted on coupling plates 50and 50a with their bottom forming portions opposed to each other. Thereare provided a high frequency anode 52 insulated from the molds andcoupling plates through an insulator 51 and a cathode 54 which ismovable in a vertical direction.

A rod 55 extends from the cathode 54, to the end of which a seat plate56 is secured. A compression spring 57 is inserted between the seatplate 56 and the coupling plate 50a, so that the cathode 54 normallycomes down to form a gap S against the anode 52. The anode 52 andcathode 54 and the insulator 51 define the contour of the bottom of thebottle. A blow pin 53 is inserted from between both electrodes 52 and 54in such a manner that it pierces the parison pinched by the mold. As thecoupling plates 50 and 50a are pivotally mounted at a pivot 62, the blowmolds 48, 49, and 48a, 49a are swingable together with the couplingplates 50 and 50a to be opened or closed.

Two pairs of nippers 59 and 59:: adapted to swing in a directionperpendicular to the split face of the mold are mounted on both ends ofthe coupling plate 50'and 50a at respective pivot 58. The nippers 59 and59a adapted to nip'the part of parison projecting from the mold areopenedtogether' with the mold when this mold opens as shown in FIG. 10,because the compression springs 61 and 61a press the nippers 59 and 59athrough metal pieces 60 and 60a. On the other hand, when the mold isclosed, push rods 64 and 64:: are pressed by push pieces 63 and 63a,thereby to push the roots of the nippers in a direction opposite toforces of the springs 61 and 61a, thus closing the nippers as shown inFIG. 9. By adjusting the positions of the push pieces 63 and 63a in thecoupling plate 50 by means of their threaded parts 65, the strength withwhich the nippers S9 and 59a pinch the parison projected from the moldcan be adjusted.

Thus, when he mold with a tubular parison enclosed therein is closed,the part of parison projecting from the ends of the mold is pinched bythe nippers 59 and 59a, so that the parison is blow molded into theshape of the mold when compressed air is injected through the blow pin53 pierced into the parison from between the electrodes 52 and 54.

After degassing through a hole made by the blow pin 53, the seat plate56 is depressed to lower the cathode 54 and press the parison therewith,whereby high frequency welding is atrained, thus sealing the bottle atits bottom.

In the case of parisons made of a thermoplastic resin, sealing of saidparison can be possible in a considerable extent by only pressing theparison before completion of its crystallization. Hence, the neck of thebottle pressed by the nippers 59 and 59a is sealed enough to withstandsubsequent operations.

The bottom of the bottle is also sealed enough to withstandtransportation even when it is completely sealed in a separate process,i.e. no electrode is provided in the mold.

When the neck of the bottle is pressed in this way, the part of materialcut ofi when the bottle is filled with contents and scrapped is veryslight, i.e. only the part on the left side of the line A-A in H6. 7 iswasted.

In the known art, as shown in FIG. 6, the end of parison 26 is pressedby a pressure piece 44 and a guide 46 is arranged at the neck so that ablow pin 45 is inserted into the parison at a portion between thepressure piece 44 and the guide 46 for bow molding, so that the holemade by the blow pin must be sealed after molding. In this case, thepart of parison on the let side ofthe line B-B is cut off and scrapped.

The tightening device 9 and the split mold 43 shown in FIG. 1 have beendescribed in detail, but in the following the invention will bedescribed in accordance with the flow of the parison. Upon transferenceof the parison from the first rotary l to the second rotary 2 at theircontact point e and immediately thereafter the mold closes. Then, whilethe table 12 rotates continuously in the direction of arrow, the processof blowing, degassing and bottom sealing are effected in succession and,when the mold reaches the position i, the mold opens to transfer themolded product to the third rotary 3. The second rotary 2 is, like thefirst one, energized through a slip ring and a brush ll fed withcompressed air through a rotary joint 16.

The third rotary 3 comprises a lower base plate 24 and an upper baseplate 23 having four sets of nippers 20, 21, tively, said nippers beingadapted to be able to open and close with signals by electric energysupplied through a slip ring l7 and a brush l8 and by compressed airsupplied through a rotary joint 19. in the center of the rotary, foursets of bottom cutters 22 are provided. These cutters are movable in thetransverse direction (right to left or vice versa in FIG. 2) by means ofa cam 25. ln pairs with the bottom cutters 22, four sets of pinholetesters 13 adapted to be moved by means of a cam 14 are arranged.Measures adapted to avoid interference of these members with the metalmolds 43 being in particular positions are provided. The construction ofthe bottom cutter 22 is shown in detail in FIGS. 13 and 14. Pivotallymounted on a pivot 73 fixed to the main body 72 are two sets ofconnecting plates 83 and 830 provided at one end with axles 74 and 74aand at the other end with blade-mounting plates 77, 77a and 78, 78athrough pivots 76 and 76a, said blade-mounting plates being respectivelyprovided with blades 79, 79a and 80, 80a secured thereto. For operation,an external tube 84 is moved transversely (right and left in FIG. 14) bymeans of compressed air. FIGS. 14 and 13(b) show the state in which theexternal tube has come to its forward position and the material has beenalready cut off. When the direction of the air pressure is reversed by asignal, the external tube retires thereby to disengage the axles 74 and740 from earns 75 and 75a and to open them under the action of a spring82 (the distance between the ends of the blades is reduced). At the sametime when pressure rolls 81 and 81a retire, the blades 79, 80 and 79a,800 are opened to reach the positions shown in FIG. 13(a). For cutting,the operations are quite contrary; that is, the body 72 advances on ashaft 85 through the cam 25 (moves to a position where the moldedproduct is cutoff), whereby, the blades are inserted between the bottomsof two molded products. When the external tube84 advances with anothersignal, the blades are at first closed to some extent by means of thepressure rolls 8! and 81a. Then, the cam 75 pushes the axle 74, therebyto open the ends of the blades in the direction of arrow (D-Da) and toforce the raised bottom of the container to be deformed. When thepressure rolls 81 and 8111 further advance, force is applied to theblades 79, 80 and 79a, 80a in the form ofa wedge, so that the extramaterial can be removed by cutting off.

The pinhole tester 13 is so constructed as shown in H0. 16. The moldedand sealed product 91 is compressed at its body for a determined timebetween a base 88 and a pressure plate respec- 87 by means of compressedair applied to an air cylinder 86. The pressure of pinholes is judgedfrom the displacement of the pressure plate 87. If any pinhole exists, alimit switch 89 is depressed for electrical control, thus permitting theproduct to be taken out into a different position. in order to be ableto ad just said displacement and the testing time, a pressing piece 90is made to be adjustable. l

The detailed motions have been hereinbefore described. To explaintheoperations along the flow ofthe product, the mold 43 of the secondaryrotary 2 opens at its contact point i with the third rotary 3 andsimultaneously therewith the nippers 20 and 21 close thereby to graspthe part of parison projecting from the mold used for transfer of theparison. When the bottom cutter 22 and the pinhole tester 13 havereached to a positionj free from any interference, the former 22 isadvanced by means of the cam 25 and cut off the extra material at thebottom of the product. At the same time, the pinhole tester 13 advancesto grasp the container at the body thereof and checks it for freedomfrom pinhole. Defective products are made to fall together with thescraps atthe position k and acceptable ones are made to fall down at theposition I.

As apparent from the above description of an embodiment of the presentinvention, the present invention has the following effects, whereby theutilization rate of the material and the operational efficiency can beremarkably improved:

I. When the parison is held by one holder 4 in the stretched condition,the backward pairs of nippers of the holder is closely followed by theforward pair of nippers ofthe next holder. It follows from this that theparison is cut between both pairs of nippers located closely to eachother, so that the wasted part of the parison is very small. These pairsof nippers may be arranged considerably near to each other. Even whenthe holders and molds are exchanged for making smaller bottles, theutilization rate of the material is far better than with the known arts.Accordingly, in the case of mass production of bottles or the like, thematerial cost can be greatly saved.

2. As the parison held in stretched state in the horizontal position istransfered, after being brought into vertical position, to the moldarranged vertically in the rotary molding machine, the operation oftransferring the parison from one circular motion to another tangentialthereto can be performed smoothly with no shock.

3. Since the parison of a length for one product is held by the holder 4in the stretched condition, inserted into the mold and blow molded,removal of the extra part of the product and separation of the productfrom the mold are facilitated.

4. Since two containers are formed at a time by combining two molds withtheir container bottom-forming portions opposed to each other, thematerial wasted between two containers is very slight, thus enhancingthe utilization rate of the material.

5. Similarly, the material wasted at the neck of the container can bealso reduced.

6. The molding efficiency can be improved by arranging high frequencyelectrodes between two containers and sealing them by high frequencywelding.

7. Since the blow pin is inserted between the bottoms oftwo containers,the hole made by the pin has not to be sealed, thus improving theoperational efficiency.

8. After taken out of the container from the mold, extra parison of themolded container can be continuously and efficiently cut off from theraised bottom.

9. While the pinhole tester serves for checking the containers as togastightness for purpose of preventing penetration of bacteria andforeign matters thereinto, it is also effective for prevention ofleakage of filling drinks or the like, became the quality of sealing atthe bottom of the container can be also judged by said tester.

We claim:

1. An apparatus for continuously manufacturing containers from athermoplastic resin, comprising a parison-transferring rotary adapted totake the parison continuously from an extruder, said rotary comprising abase rotating around its center axis, several support rods projectedlaterallyfrom said base and arranged at equal intervals around saidbase, a tube fitted loosely on each of said support rods and controlledfor movement along said support rod and for rotation by 90 with respectto rotation of said base, connecting pieces fixed to the forward pair ofthe nippers are made to grasp the parison to stretch it withthe rotationof said base for moving said nippers at a linear velocity higher thanthat at which the parison is extruded from said extruder and then thebackward pair of the nippers'nips the parison and at the same time asthis nipping the forward pair of nippers of the succeedingparison-holding nieansgr'aspsthe parison, said cutting blades beingarranged sothat the'pa rison is cut off at a position between said bothpairs of nippers, and said parison-holding means being constructed andarranged in such arnanner that said holding means rotates by'90 aftersaid cutting of the parison thereby to bring the-cut and stretchedparison held as above into parallel to the rotating axis of said base toinsert it into one of twopiece split metal molds of the followingblow-molding rotary, said molds being mounted in parallel to said rotaryaxis; and a blow-molding rotary comprising a rotating disc, severaltightening devices arranged'at equal intervals around said .disc, saidtightening device including said split mold constructed to have atformobtained by joining bottom portions of two containers, a blow pinadapted to be inserted between the bottoms of two containers to beformed, and nippers mounted on bothends of one'split of said split moldin the direction at right angle with the split surface of the mold, saidnippers being adapted to open when the mold is opened and close rdarranged at equal interval around saidbase, a tube fitted lobsely oneach of said'suppo'rt' rods and controlled for movemerit-"along saidsupport rodand for rotation by 90. with respect to rotation: of saidbase, connectingpieces fixed to the outer end of said tube so as to forma T-shaped, holding means comprising two pairs of nippers secured toboth ends of said connecting pieces and adapted to be opened .and closedin relation to the rotation of saidbase, and cutting blades provided onone of said pairs of the nippers located forward with respect to thedirection of rotation of said base, whereby said forward pair of thenippers are made to group the parison to stretch it with the rotation ofsaid base for'moving saidnippers at a linear velocity higher thanthat'at which the parison is extruded-from said extruder and thenthebackward pair of the nippers nips the parison and at the same time asthis nipping the forward pair of nippers of the succeedingparison-holding means grasps the parison, said cutting blades beingarranged so that the parison is cut off at a position between said bothpairs of nippers, and said parison holding means being constructed andarranged in such a' manner that said holding means rotates by 90 aftersaid cutting of the parison thereby to bring the cut and stretchedparison held as above into parallel to the rotating axis of saidbase-andto insert it into one of two-piece splitmetal molds of thefollowing blow-molding rotary', said molds being mounted in parallel tosaid rotating axis; and a blow-molding rotary comprising a rotatingdisc,-several tightening devices arranged at equal intervals varoundsaid disc, said tightening device including said split mold constructedto have a form obtained b joining bottom portions of two containers, ablow pin adapted to be inserted between the bottoms of two containers tobe formed, and nippers mounted on both ends of one split of said splitmold, in the direction at when the mold is closed thereby to compressthe parts of the parison projecting from the ends of the mold; and meansadapted to rotate synchronously and continuously said two rotarics.

2. An apparatus for continuously manufacturing containers from athermoplastic resin, comprising a parison transferring "rotary adaptedto take the parison continuously from an exttuder, saidrotary'comprisinga base rotating around its center axis, several support rods projectedlaterally from said base being adapted to open when: the mold is openedand close when the mold is closed thereby to compress the parts of the.

parison projecting from the ends of the mold; a takeoff and trimmingrotary comprising means for taking continuously and automatically thecompleted product, means for cutting 'off e'xtra'matcrial at the bottomof the product, means for pressing central portion of the productthereby to check existence or nonexistence or pinhole, and means forsorting acceptableor not; and means adapted to rotate synchronously andcontinuously said rotaries.

2. An apparatus for continuously manufacturing containers from athermoplastic resin, comprising a parison transferring rotary adapted totake the parison continuously from an extruder, said rotary comprising abase rotating around its center axis, several support rods projectedlaterally from said base and arranged at equal interval around saidbase, a tube fitted loosely on each of said support rods and controlledfor movement along said support rod and For rotation by 90* with respectto rotation of said base, connecting pieces fixed to the outer end ofsaid tube so as to form a T-shaped, holding means comprising two pairsof nippers secured to both ends of said connecting pieces and adapted tobe opened and closed in relation to the rotation of said base, andcutting blades provided on one of said pairs of the nippers locatedforward with respect to the direction of rotation of said base, wherebysaid forward pair of the nippers are made to group the parison tostretch it with the rotation of said base for moving said nippers at alinear velocity higher than that at which the parison is extruded fromsaid extruder and then the backward pair of the nippers nips the parisonand at the same time as this nipping the forward pair of nippers of thesucceeding parison-holding means grasps the parison, said cutting bladesbeing arranged so that the parison is cut off at a position between saidboth pairs of nippers, and said parison holding means being constructedand arranged in such a manner that said holding means rotates by 90*after said cutting of the parison thereby to bring the cut and stretchedparison held as above into parallel to the rotating axis of said baseand to insert it into one of two-piece split metal molds of thefollowing blow-molding rotary, said molds being mounted in parallel tosaid rotating axis; and a blow-molding rotary comprising a rotatingdisc, several tightening devices arranged at equal intervals around saiddisc, said tightening device including said split mold constructed tohave a form obtained by joining bottom portions of two containers, ablow pin adapted to be inserted between the bottoms of two containers tobe formed, and nippers mounted on both ends of one split of said splitmold in the direction at right angle with the split surface of the mold,said nippers being adapted to open when the mold is opened and closewhen the mold is closed thereby to compress the parts of the parisonprojecting from the ends of the mold; a takeoff and trimming rotarycomprising means for taking continuously and automatically the completedproduct, means for cutting off extra material at the bottom of theproduct, means for pressing central portion of the product thereby tocheck existence or nonexistence or pinhole, and means for sortingacceptable or not; and means adapted to rotate synchronously andcontinuously said rotaries.